In the rich text editor:
@Kaleo
In a comment:
[Kaleo](https://chowlings.com/user/Kaleo)
For Names and Avatars:
In the rich text editor:
%Kaleo
In a comment:
[![Kaleo's Avatar](https://chowlings.com/images/avatars/default.jpg)](https://chowlings.com/user/Kaleo) [Kaleo](https://chowlings.com/user/Kaleo)